CoastLineMaker - can't make changes

I thought I had this, but returning to the prog to make some changes (a few minor coastline position adjustments) after a looong break from it, I just can't get CLM to work.CLM2 and all the bits are installed correctly. I've got my grid setup fine - it's only a 2 high x 3 wide LOD 13 area.I follow the instructions explicitly (for the fortieth time!), save my project and get my **-VTP.asm file. VTP checks out fine - no erros. It compiles and I move the **VTP.bgl into my scenery folder - and nothing changes.I'm doing (or not doing) something stupid. What on earth is it?